Lens centering, marking, and testing instrument



Jul 21, 1942;

w. A. LOCKHART 2,290,556. LENS CENTERING; MARKING, AND TESTINGINSTRUMENT Filed Dec. 20, 1938 v 4 Sheets-Sheet 1 l3 2 I22 EL 1 m2. 3 /01can a 9 l0? 00000000 06o l0, 7 ,5 V I 5/ 5 Q 9 2 i Y lO/ INVENTEIR I IILUAMALUBKHART ATTn nEY y 1942- w. A. LOCKHART 229G566 LENS CEHTERINC',MARKING, AND TESTING INSTRUMENT Filed Dec. 20, 1938 4 Sheets-Sheet 2LEJNSET E 5 lIP REINSET REJIUTSU as. up LEJIIJTSET Rmszr as. now LEJNSEI6 l0 I5 20 25 LEOVTSET m nown REDUTSET 48 IHVENTDH WILL/AM A.LULKHARThfm ATT URHEY July 21, 1942- w. A. LOCKHART 2,290,566

LENS CENTERING, MARKING, AND TESTING INSTRUMENT Filed Dec. 20, 1938' 4Sheets-Shet 3 E 1-83 as 8788' 52 28 WmmnALqcKHART ATTORNEY A.v LbcKHART2,290,566

LENS CENTERING, MARKING, AND TESTING INSTRUMENT Filed Dec. 20, 1958 4Sheets-Sheet 4 a INV'ENT u R WILLIAMALUL'KHART ATTORNEY Patented July21, 1942 LENS CENTERING, MARKING, AND TESTING INSTRUMENT William A.Lockhart, Newark, N. J., assignor to Shuron Optical Company, Inc.,Geneva, N. Y., a corporation of New York Application December 20, 1938,Serial No. 246,863

6 Claims.

This invention relates to an instrument for marking a semi-finished lensblank and particularly for locating the relative positions of thereading section, axes and optical centers of bifocal lens blanksaccording to a certain prescription preparatory to finishing the lensaccording to other coordinated prescriptions, as may be required in theproduction of the lens. Also for checking the finished lens to ascertainthe accuracy of the grinding and polishing operations with respect tothe prescriptions and for accurately marking or inscribing the base linethere- The lens blank to be operated upon by this instrument is composedof suitable glass which may have a reading section or segmentincorporated therein. The blank has one surface ground and polished tothe contour required for the finished lens, leaving the other surface tobe ground and polished to a certain prescribed contour coordinated withthe previously finished contour in such manner that when th lens is cutfrom the blank, finished and mounted, its optical properties willconform to certain predetermined prescriptions.

An object of the invention is to provide simple and efiicient means forexpeditiously locating the relative positions of the reading section orsegment, optical centers and axes on semi-finished lenses as they shouldappear on the finished lenses according to certain predeterminedprescriptions, so that the marked lenses may be accurately positioned inthe grinding and polishing machine for finishing the unfinished surfacesof the lenses according to the predetermined prescription.

Another object of the invention is to produce an instrument of the abovementioned class which may be utilized for testing the ground lenses todetermine the accuracy of the grinding operation and also to test out orcompleted lenses to check the optical axis thereof with theprescription.

A further object of the invention resides in producing an instrumentwhich may be readily used for testing prisms as well as lenses.

More specifically, this invention contemplates the provision of aninstrument for marking, centering and testing lenses, prisms or the likewherein is provided a target, a sight opening spaced from the target anda lens support mounted intermediate the sight opening and the target.The target, lens support and sight opening are arranged in alignment onewith the other, the target being adjustable toward and from the lenssupport to adapt the same for different powered lenses.

The machine is further provided with a segment locator adjacent the lenssupport and movable relative thereto for indicating the position of thereading segment of a bifocal lens with respect to the center or opticalaxis of a semifinished lens blank both as to the amount of drop and tothe inset, or outset, of the segment.

The invention further provides an instrument of this class wherein thelens may be positioned with the eye-side thereof facing downwardly orfacing upwardly and wherein the reading segment may be inset or outsetwith respect to the center of the lens. It also provides means whereby,when the lens is placed on the lens support, the outline of the readingsegment will be visually contrasted with the remaining portions of thelens blank by the use of a source of light so placed that the light willmost efiicaciously pass through the segment and adjacent portion of thelens blank;

Another object is to provide means for adjusting the source of lightwith respect to the lens support to governthe effective amount ofillumination of the target and lens;

A further object is to provide the instrument with an ink pad holder anda marker supporting carrier mounted and operated in such manner that themarker may be moved from engagement with the ink pad into engagementwith the surface of the lens blank and vice versa for marking theoptical center, the optical axis and the mounting line on the lens,saidcarrier being provided with anangularly adjustable holder having adiametricalrow of marking pins adapted to be moved alternately intoengagement with the inking pad and with the lens blank.

These and other objectsand advantages will more fully appear from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

Figure 1 is a top plan of an instrument constructed in accordance withthis invention.

' Figure 2"is a longitudinal sectional view taken substantially on line2-2, Figure l, a portion of the base being broken away.

Figure 3 is a detail vertical sectonal view taken on line 3-3, Figure 5.

Figure 4 is a detail vertical sectional view taken on line 4-4, Figure2. 7

Figures 5, 6,7 and 8 are horizontal views taken, respectively, on lines55,' 6- -6, 1- 1 and 88, Figure 2, I,

Figure 9 is an enlarged detail vertical view,

Figure 13 is a detail vertical sectional view taken on line l3-I3,Figure 8.

Figure 14 is a horizontal sectional view taken on line l4-l4, Figure 13.

Figure 15 is a vertical sectional view taken on line l5-l5, Figure l.

Figures 16 and 17 are detail horizontal sectional views taken,respectively, on lines l6-l6 and Il -41, Figure 15.

Figure 18 is a transverse vertical sectional view taken on line l8l8,Figure 5.

Figure 19 is a side elevation of a gauge wire adapted to be used withthe lens support when testing finished lenses;

This instrument, as illustrated, comprises a main supporting frame[consisting of a cylindrical base member 2, a supporting ring 3 mountedon the upper end of the base 2 and a tubular standard 4 secured tothering 3 to extend upwardly therefrom in substantially coaxial relationwith the base 2. The base 2, as shown, is provided with verticallydisposed slots 5 for lightness and to provide air passages forventilating the interior thereof.

Mounted in the base 2 intermediate the ends thereof is a plate 6 whichis rotatably connected with the base by a pair of pins 1 connected atdiametrically opposite sides of the plate and which extend outwardlytherefrom in substantially coaxial relation with each other throughcorresponding holes provided in the'base 2, see Figure 4. To the outerend of' one of thepins l is secured a handle 8 by which the plate 6 maybe manually rotated.

An electric lamp socket 9 secured to the central portion of the plate 6supports an incandescent lamp l6. Mounted within the upper portion ofthe base 2 is a cylindrical reflector II which surrounds the lamp H] fordirecting the light rays from the lamp l0 upwardly through the interiorof the standard 4. The upper side of the plate 6 may be polished so asto produce a reflecting surface adapted to cooperate with the reflectorI I for directing the light rays upwardly through the inner chamber 12of the standard 4 substantially centrally thereof when the plate is in ahorizontal position. When the plate is in a more or less angularposition with respectto the horizontal the light rays are directedthrough the chamber 12 at an angle to the axis thereof. In other words,a light spot of relatively high intensity is produced by the coaction ofthe'lamp It and the reflectors 6 and II on a lens carried by a lensholder I3 mounted at the upper end of standard 4 and the position of thelight spot upon the lens may be readily controlled to obtain the mostefficacious results by swinging the plate 6 and lamp I0.

Mounted within the chamber 12 beneath the lens holder I3 is a target I4.This target, as shown more clearly in Figures 2, 8 and 14, consists ofan annular frame or ring l5 of slightly less exterior diameter than thediameter of the chamber I2 so as to move freely both vertically androtatively therein. The frame I5 is provided with a pair of guide wiresI5 which extend diametrically across the frame at substantially rightangles to each other. The frame I5 is rotatably mounted upon an annularsupport I! which is seated in a peripheral recess l5 provided in thelower outer portion of the ring l5, as shown in Figure 13.

The support I! has secured to one side thereof a pin or stud [8 whichextends outwardly therefrom through an elongated vertically disposedslot I9 provided in the wall of the standard 4. The outer portion of thestud I8 is carried in a slide plate 20 which is mounted for verticalreciprocative movement in slot [9. The plate 25 has the oppositevertical sides thereof provided with tongues or flanges 20' which ridein corresponding grooves or recesses 2| provided in the inner adjacentvertical edges of a pair of gibs 2| secured to the outer side of thestandard 4 as illustrated in Figure 8.

A shaft 22 is journaled in the upper portion of the slide plate 20,asshown in Figure 13. The inner end of the shaft 22 is provided with apinion 23 which is in' meshing engagement with rack teeth 24 provided'onthe upper edge surface of the frame l5. The outer end of the shaft 22 isprovided with a handle 25 by which the shaft may be rotated forproducing rotary movement of the frame [5 and guide wires it connectedtherewith with respect to support IT. The handle 25 may also be utilizedto'producc vertical movementof the plate 20 and the members carriedthereby for bringing the target into proper spaced relation to a lenscarried by the lens holder [3, depending upon the focal power of saidlens.

In order to prevent dust or other foreign matter from passing throughthe slot l9 into the chamber l2, dust pads 26 may be secured, as shownin Figure 8, to the exterior surface of the gibs 2| to extend acrosstheslot. The adjacent vertical edges of 'thedust pads are arranged tocontact with'each other substantially midway between the'sides of theslot so as to permit the ready movement of an outwardly projecting ribportion 20" of the plate 20 with respect to said pads during thevertical movement of the target. e,

The hereinbefore mentioned lens holder l3 comprises a transparentwindow'or table 28 com" posed, in this instance,'of two superposed discsof glass or the like and which is'carried by an annular frame'29 mountedonthe upper end of a housing member 30.'secured by bolts 3| to the upperend ofthe" standard 4, see Figure 6 and 10. The lens supporting frame 29is provided with a pair of diametrically disposed peripheral flanges 32which extend downwardly over the adjacent upper portion of the housing33 and screws 33 are mounted in-said flanges for engagement with theadjacent peripheral surface of the housing 30 for r'eleasably securingthe frame to said housing, as shown in Figures 6 and 9. The uppersurface of the frame 29 is provided with a graduatedscale 34 surroundingthe upper disc of the window 28, said scale being graduated in oppositedirections from' a zero position to indicate progressively differentdegrees of a circle. as shown" more clearly in Figure A clamp arm 35 ismounted, as shown in Figure'5', to extend inwardly from one side of theframe 29 to substantially 'the'center of the window"28 for releasablyholding a lens on' said window? The arm 35, as shown more'particularlyin Figure 3, is provided with a pin 36 atthe outer end thereof whichextends downwardly through a suitable opening provided in one of theflange members 32 of the frame 29.- The lower end of the pin 36terminates some distance below the flange 32 and is adapted to beengaged by a rock arm 31 pivotally mounted, as at 38, intermediate theends thereof to the adjacent peripheral portion of the housing 39. Theother end of the arm 31 is in the path of movement of a plunger 39 whichis also slidably mounted in the flange 32.

The arrangement of the pin 36, arm 31 and plunger 39 is such that whenthe clamp arm 35 is in its lowermost position the plunger 39 will bemaintained in its uppermost position as shown plunger 39 for releasingthe lens clamped to V provided with a dowel pin 42 which is slidablyreceived in a suitable aperture provided in flange 32.

The housing 39, in this instance, is a ringlike member mounted insubstantially coaxial relation with the standard 4 and is provided withan inwardly extending annular flange 44 at the lower end thereof, asshown more clearly in Figure 10. Mounted upon the flange 44 is a ring 45which carries a translucent window 46 composed preferably of colored orstained glass adapted to receive the light from the lamp l9therethrough. Mounted upon the ring 45 is a second ring 41 which, inturn, carries an objective lens 48 arranged over the window 46. A thirdring 49 is mounted within the housing 39 over the second ring 41. Thisthird ring carries a dial 59 composed of glass or other suitabletransparent material which is adapted to receive the light from the lamp|9 passing through the window 46 and lens 49.

The upper surface of the dial 59 is provided with a graduated scale 5|,as shown in Figure 6, said scale being graduated in opposite directionsfrom a zero position at the center of the dial and in coaxial relationwith the standard 4 to indicate progressively increasing value inmillimeters for determining the amount of drop of the reading segment ofthe lens with respect to the optical center of said lens. It ispreferable that the scale 5| be arranged, as shown in the drawings, toextend substantially normal to the axis of rotation of the reflector 6so that the light spots produced by the coaction of lamp I9 andreflector 6 may be moved longitudinally of the scale by rocking saidlatter members about the axis of pin 1 to successively illuminatevarious portions of the scale. Each of the rings 45, 41 and 49 arepreferably composed of relatively hard resilient material, such asfibre, and are provided with grooves on their inner edges for thereception of the marginal edges of the corresponding window, lens ordial member supported thereby.

Each of these rings is split at one side, as indicated more particularlyin Figures 6 and '1, and is secured to the housing 39 in clampingengagement' with the membersupported thereby by a plurality of, in thisinstance four, screws 52, as indicated in'Figure 6.

It will be understood that the window 46, ob

jective lens 48 and dial 59 are arranged beneath the. lens holder |3 sothat the position of the reading segment ona lens mounted on said holderThe upper surface of the intermediate ring member 41 is provided with arecess 54 arranged at one side thereof for the reception therethrough ofa pair of guide or caliper fingers 55. These guide fingers have theinner ends thereof curved inwardly toward each other to provide points55' arranged in opposed relation to each other and which are adapted 'toalign with opposite sides of the reading segment of a lens mounted onthe lens holder I3. These guide fingers extend outwardly through saidrecess 54 and through a similar recess 56 provided in the adjacent sideof the housing 39 at the upper end thereof, see Figure 1.

The outer ends of the guide fingers 55 are secured byscrews 51 to nutmembers 58 which are mounted upon a shaft 59 in screw-threaded relationtherewith. The shaft 59 is rotatably mounted at the upper end of a frame69, as shown more particularly in Figure 9, and which in turn is mountedfor both rocking and lateral movementupon a bracket 6| carried by thestandard 4 in a manner presently described.

The shaft 59 is provided with right and lefthand screw-threads 59 and59" arranged interv mediate a pair of upwardly extending arms 62 of theframe 69, said screw-threads being engaged by the nut members 58,respectively. One end of the shaft 59 is extended outwardly beyond theadjacent arm 62 and has secured thereto a knurled disc 63 by which theshaft may be manually rotated. The disc 63 is provided with a relativelylong hub portion 64 which extends from -the disc 63 inwardly to theadjacent arm 62 of frame 69, said hub being provided with screwthreads65 upon which is mounted a nut member 66.

The nut member 66, in this instance, is provided with a V-shapedmarginal edge adapted to align with a graduated scale 61 provided on aplate 63 mounted on a bracket 69 secured to the frame 69. The marginaledge of the nut member 66 is provided with a transversely disposedrecess 66 which, as shown in Figure 11, receives the ad- I9 to 25 inFigure '7 of the drawings.

other.

The manner of connecting the frame 66 with,

the bracket 6|, in this instance, consists in pro-- .viding the bracketwith a horizontally disposed hole 19 in which is mounted a pair ofsupporting pins 1| and 12. The pin 1| is secured to the bracket, 6| by ascrew 13 and extends outwardly from one end of the hole 19 through asuitable opening provided in the adjacent one of a pair:

is free to move longitudinally of the pin and to rock about said pin asa pivot. The pinlZ haslever extends some distance above the pivot 11'and is provided with a finger ring I8 whereby the lever may be manuallyrocked toward or from the bracket 6i. The-lower end ofthe lever I6 ispivotallyconnected, as at I6, to one end of a link 79 which extendssubstantially parallel with the pin 72 through a slot I4 provided in thelower end of the arm 14 connected with the pin II and is slidablysupported in said slots by a screw 80. The end of the link' I9 adjacentthe slot I4 is bent. upwardly and received in an annular groove BIprovided in the periphery of the fixed rod II adjacent the outer endthereof.

It will now be observed that inasmuch as the pin II is held againstmovement with respect to the bracket BI rocking of the lever 16 aboutthe pivot I6 from the intermediate position indicated by full lines inFigure 9'to one or the other of the extreme positions, as indicated bythe broken lines X, will produce a corresponding lateral movement of theframe 60 and, therefore, of the guide fingers 55 carried thereby.

Furthermore, it will be observed that due to the connection of the lever76 withthe pin 12',- the frame 68 may be rocked about the axes of thepins Hand 12 to move the upper portion of the frame toward or from thehousing 38; This swinging movement of the frame toward and from thehousing will produce a corresponding movement of the guide fingers 55from a position substantially in alignment with the center of the dial58 outwardly toward the edge of said dial or vice versa. This lattermovement of the frame 69 and the guide fingers is for the purpose ofarranging said fingers at one side or the other of the vertical planepassing through lens holder I3 at the -l80 position on the scale 34 fordetermining the amount of drop of the reading segment of the lens.

In order that the amount of inset or outset of the guide fingers may bereadily determined, I have provided an index plate 831- whichis mountedover a chart 84 carried in substantially a horizontal position by aplate 85 secured to the housing 30 by screws 86 to project outwardlytherefrom in a plane over the guide fingers 55; The index plate 83 issecured by a screw 81 to a slide plate 88 mounted in a horizontal planeintermediate the guide fingers and the plate 85 to slide between a pairof guide rails 89 secured to plate 85, as shown in Figures and 12.

The slide plate 88 is provided with a boss 88' which extends upwardlytherefrom through an elongated slot 85 provided in the plate 85 andchart 84 into a shallow recess provided in the lower face of the indexplate 83, the screw 81 being screw-threaded in said boss. The lower sideof the slide plate 88 is provided with a groove or recess 98' extendinglongitudinally thereof from front to rear and which receives therein theof downwardly extending, arms 14 of the frame 68. The pin II is slidablyand rotatably received in the Opening in the frame arm so that theframepp r nd f a DinBlClamP d .1e .framefill by the bracket 99.

It will now be seen that-when the-framewis moved laterally acorresponding: lateral movement of the index plate 83 will beproducedthereby through the; medium of they-pin 9|; Duringv the rockingmovement of the frame 68; however, the index plate ;83, will remain.stationary due to the movement of the pin 9| through thegroove or recess98. In orderthattheamount of lateral movement of the-index plate, 83 maybe readily determined, the chart- Mris provided with two graduatedscales 92 on the upper surface thereof comprising parallel linesadaptedto align with the longitudinal edges 83' of theindex plate. The distancefrom theexterior side of'one scale 92 to theexterior side of the otherscale 92 is substantially equal to the width of 4 the index plate 83 sothat when said indexplate. and the guide fingers 55 are in their centralposition,

said edges 83' of the plate willregister with the.

outer positioned lines ofthe corresponding scale 92, as indicated inFigure 5.

The lines of each scale 92 :are arranged; in this instance,substantially one millimeter apart-so that when theindexplateismovedlaterally in either direction,- the amount of said movement may bereadily determined by the alignment of an edge 83' of the indexplatewithsaid scales, the edges 83' being beveled to render the readingto be quickly and accurately made.

The bracket BI may be mountedon thestandard 4 in any suitable manner.However; in order to provide for lateral adjustment of the bracket, Ihave shown the same secured by screws 93 to a slide 94 mounted ona-block95 securedto the standard 4, as shown in FigurelOs The guide block isprovided with a, dovetail tongue or flange 95' which is slidablyreceived-in a corresponding dovetail recess 94 providedin the inner faceof the slide 94.

A wear plate 95 is mounted between the lower edge of the flange 95'; andthe adjacent side of the recess 944. The slide 94'isreleasably clampedto the block 95 byscrews 91 mounted in the lower M arlcing mechanismConnected withthe housing 30-at theside thereof opposite the segmentlocating mechanism is a shelf or extension 98 .to-which is secured abracket 99. This bracket 99 is provided with an extension 99 whichprojects rearwardly and supports an inkwell I89. The inkwell I99 may berotatably connected with the extension 99', as shown in Figure 18, sothat the position thereof with respect to the marking elements. may bechanged.

A carrier frame IOI is rotatably connectedat one end to a shaft I82fixedly secured in suitable bearing members I 03 providedon the bracket99 to swing about a horizontal axis at rightranglcs to the longitudinalcenter of the standard 4. The opposite end of the frame I81 I isbifurcated and provided with transversely; spaced coaxial bearing pinsI04 arranged substantially parallel with the bearings I93; The innerendsof the bearing pins I04 project toward eachother for supporting aring-shaped housing Iwhich is secured to the inner ends of the bearingpins by screws I86, Figure 18, or equivalent fastening means, the pins.being a engaged in diametrically. opposed rad al openings in saidhousing,

The outer end of one.of..the.bearing..pins;I I has secured thereto'acircular disc. or pulley I0 I. A similar disc or pulley I08 is securedtothe shaft I02 in alignment with the pulley I0I.. The pulleys I01 andI03 are connected to each other. by a flexible metal strap or belt I09secured to the pulleys, as by screws IIO, so that the pin I04 and thehousing I05 connected thereto will be maintained against rotation withrespect to the shaft I02 and the housing member 30 when the frame IOI isswung about the shaft I02 as an axis. In other words, the housing I05 ismaintained in substantially a horizontal plane in all positions of theswinging frame I0 I. The shaft I02 is positioned substantially midwaybetween the inkwell I00 and the lens holder I3 so that as the frameIOIis moved from its outermostposition to its innermost position thehousing I05 will be moved from a position over the inkwell I00 to aposition over. the window 28 of the lens holder I3 or vice versa.

lniorderv that the frame IOI may be'readily moved about the shaft I02,said frame'isprovided with a handle II I secured to the outer end of theframe opposite the pulley I0I. The upper surface of the housing I05 isprovided with diametrically opposed series of graduations II2 graduallyincreasing in value from zero at one side to 180 at the opposite side.One set of graduations is used to indicate the degree of angularadjustment of the marking pins presently described from the zeroposition for marking on'a convex surface as when the eye-side of a lensis placed facing down and the other set for marking upon a concavesurface as when the eye-sideof a lens is placed facing up.

A circular, tool-supporting block H3 is journaledfor rotary movementwithin and upon the housing I05 substantially coaxial therewith and isheld against axial displacement by'an upper shoulder lll'provided onsaid block and seated in a corresponding recess in the upper inner edgeof the housing I05 and a pair of screws I I5 screwthreaded in the lowerportion of the block at diametrically opposite sides thereof, the headsof said screws being arranged in overlying relation with the adjacentlower surface of the housing I05. The tool supporting block H3 may bereadily removed from the housing I05 when desired by simply removing thescrews II5.' This block I I3 is provided with a central coaxial socket II6 and similar additional sockets I I0 extending radially from thecentral socket and also circumferentially about the block in slightlyinward spaced relation to the peripheral edge thereof. The sockets areall arranged in parallel relation with each other and open from theunder side for receiving a corresponding number of marking pins Ill andIII which are similarly arranged in parallel relation in theirrespective sockets.

The upper ends of the pins H1 and III are reduced in diameter and extendthrough corresponding reduced openings in the upper end walls of thesockets to permit vertical movement of the pins, said pins beingmaintained, in this instance, in their lowermost position by gravity.The upper reduced ends of the marking pins are provided withscrew-threaded apertures for receiving suitable screws I I0 having headsI I8 adapted to engage the upper face of the tool block for limiting thedownward movement of the pins and also for setting the marking pins sothat their lower marking points will be normally disposed inapproximately the same horizontal plane. The object of this movablymounting. .the marking :pins in'tliezholder block -I I3. is to"permit'their: points-to c on'formto the contour of the lens blank duringthe marking'o'peration and also to permit the marking points to contactsubstantially uniformly. with the inking pad, as H0," mounted intheinkwell I00. The holderor block H3 is provided with diametricallyopposite index lines I20 adjacent the periphery thereof and in alignmentwith the radially disposed row of marking pins to register with any oneof the graduations I I2 on the upper face of the housing I05,as theholder is rotated, thus permitting the diametrically disposedmarkingpins to be positioned to any desired angle for markingthe opticalcenters and axes upon the lens blank according to certain prescribedformulae required for the finished lenses. The angular adjustment of theholder is'effected by hand and for this purpose two of the screw-heads,as IIB, positioned at diametrically'opposite sides of the block, may bearranged as illustrated in Figure 18 to extend some distance above theupper face of the supporting block when the pins are in their lowermostposition to provide fingerpieces whereby the block may be manuallyrotated;

As before stated, the diametrically disposed optical center and axesupon the lens blank, while the pins disposed about the axis of thecenter pin adjacent the periphery of the block are for marking the lensat corresponding points to be used for gauging the thicknesses of thelens at these points so as to avoid the formation of prisms during thegrinding operation.

The rotation of the supporting block H3 to properly position the markingpins H5 and Mt for marking the optical center and axis upon thelens-blank is usually accomplished when the frame "IOI is in itsoutermost position with the marking pins in engagement with the inkpadcarried by the inkwell. It will, therefore, be observed that anotherpurpose of rotatably mounting the inkwell'upon the bracket is to permitthe inkwell to rotate in unison with the block and pins during thisangular adjustment of the P Eye-piece In order to assist the operator inproperly positioning a lens upon the lens holder, I have provided thisinstrument with an eye-piece I22 which, as shown more particularly inFigures 2 and15, is a hollow, frusto-conical shaped member open at thebottom and having a peep aperture I23 provided in the upper end wallthereof. The eye-piece I22 is secured to an arm I24 which has an upperhorizontal portion extending out-- wardly from the eye-piece and asubstantially vertical portion extending downwardly from the horizontalportion.

The lower vertical portion of the arm extends through a bracket I25secured to a laterally projecting shelf I20 formed on the standard 4 atone side thereof. The arm I24 is mounted in the bracket I25 for verticaladjustment and in order to frictionally maintain the arm in the adjustedsaid screw or pin being seated in a recess provided in thejadjacentportion of thekey.

The groove. I28. and the adjacentinner 'sideof the .key I2I areV-shapedin cross section, as 11- lustrated in Figure 17, so that said keyfunctions to maintain the arm I24 against rotary movement. Afingerpiece, as I33, may be secured, as shown in Figure 15, to the lowerend of:the arm I24 to extend downwardly some distance below the bracketI whereby the arm and eye-piece I22 may be readily moved vertically. Thedownward movement of the arm and eye-piece I22 is limited by a stop studI3I mounted in the arm I24 above the bracket I25 and which is adapted toengage the upper end of .a stop pin I32 secured in the upper end of thekey I2I. The arm I24 may also be adjusted vertically bymeans of a pinionI 33mounted On a shaft I34 journaled in suitable bearings I35 provided.on the bracket I25, said pinion having meshing engagement with rackteeth I36 provided in the peripheral surface of the arm I24 at one sideof the. groove I28.

One end of the shaft I34 extendsbeyond the bracket I25 and is providedwith aknurleddisc I31, see Figure 1, by which the shaft and pinion maybe manually rotated.

As a further means for assisting the operator be provided with areflector I4I mounted; on the socket I39 for directing the raysof lightfrom said lamp upon the lens or inkwellas maybe desired.

Asafurther aid for the operator, I havezprovided the eye-piece I22 witha magnifyingglass; I43 which is mounted in a case I44 pivotally con- .1-nected by a screw I45-with the arm I24'adjacent, The case I44 is mountedto the eye-piece I22. swing in a horizontal plane beneath the eyepiece I22 from a position in coaxial alignment with the peep aperture I23 to aposition at one, side of the eye-piece out of the line of vision-- ofthe operator when sighting through the eyepiece.

Operation.

When marking a semi-finished bi-focal lens, there are at least threefactors to be determined in accordance with a predeterminedprescription, namely, the desired position of the optical center of thelens with respect to the drop of the reading segment, the position ofthis centerv with relation to the inset or, in certain .instances, theoutset of the reading segment and the angle of position of thecylindrical axis.

These factors being determined, the instrument-is-adjusted accordinglyby first moving the guide fingers to the right or to the left; if theyare not alreadyin their proper position, by

swinging the lever 16 toward or from theframe until an edge 83 of theindex plate-83 is Thescale 92 arranged adjacent the right-hand edge ofthe index plate .83 is used for a lens positioned with the eye-side upwhen 'wishing to determine aligned with the properline of a-scale 92.

the right eye inset or the left eye outset, and

when thelens is positioned with the eye-sidedown. for the left eyeinsetor the right eye outset. The scale 92 adjacent the left-hand edge of theindex plate 83 is used when the lens is. positioned with the eye-side upto determine the left eye inset or the right eye outset, or if thelensispositioned with the eye-side down to determine the right eye insetor the left eye outset, as indicated in Figure 5. The guide fingers maythen be adjusted toward or from each other to bring the points 55thereof spaced from each other a distance equal to the width of thereading segment. The supporting block II3 of the marking mechanism maythen be adjusted, when necessary, with respect to the housing I I15 tobringthe index line I20 along its scale II2 to one side or the other ofthe zero graduation so as to register with the graduation correspondingto the prescribed angle of inclination of the cylindrical axis ofv'thelens .to the horizontal axis or mounting line.

The lens to be marked may now be mounted on the lens holder I3 beneaththe inner end 40 of the. clamp 35, the lens. is usually placed with theconvex or finished side thereof uppermost. The lamp I0 may now beenergized in any convenient manner and the eye-piece I22 adjustedvertically so as to enable the operator to see most clearlyf through thelens and standard chamber I2.

When a finished lens is to be marked, the lamp I 0 .is adjusted byswinging handle 8 about the vertical position for obtaining the maximumillumination of the reading segment of the lens and. illuminate thetarget cross wires I6; When a bi-focal lens is to be marked, the lampmay be tilted with respect to'the vertical so as to eliminate glare. Thetarget I4 may now beadjusted vertically by up or down movement of thehandle 25 to the required axis for the focal power of the lens. Thetarget may then be adjusted angularly by rotation of the handle 25 tobring one or the other of the cross wires Ifiinto alignment with the.0-180 line-or anyvother required degree line onthe scale 34.

The lens may now be adjusted with respectto the window 28 of the lensholder to bring the upper-edge of the reading segment the requireddistance below the optical center of the lens, as determined by thescale-5I on the dial5Il. That is, to bring the upper edge of ;thesegment into alignment with the graduation on" the scale 5|corresponding to the amount of drop called for in the prescription. Atthe same time, the lens is adjusted so as to bring the side edges of thesegment into alignmentv with the corresponding. points 55' of the guidefingers 55'to obtain the required insetor, in certain instances, outsetof the reading segmentas-called for in the prescription;

The mark ng device is then'rocked about the axis of shaft I to bring themarking pins 5' and II 6' from theinoperative position inengagement'with the ink pad to the operative position .into engagementwith the upper surface of the lens blank for marking the optical centerof the lens and the position of the cylindrical axis lindrical surfacefor producing a toric lens.

After the lens has been ground, the accuracy of the grinding operationmay be readily determined by my novel instrument by again placing thelens. upon the window 28 0f the lens holder with theconvex sideuppermost and with thereading segment positioned between the points 55'of the guide fingers 55 and at a distance below the center of the scalecorresponding to the amount of drop of the segment called for in theprescription.

Now, by rotating the target I4 until the cross wires it appear unbrokenthroughout their length at the edges of the lens to determine the actualmajor and minor axes of the lens produced by the grinding operation, thedegree of accuracy of the grinding operation may then be readilydetermined by observing the position of the cross wires of the target,as indicated by the scale 34 provided on the lens support. The cuttingor base line of the lens may now be readily marked on the lens by movingthe supporting block H3 with respect to the housing N to bring the indexlines I into registration with the line 0-l80 line on the scale H2,after which the frame llll may be rocked forwardly to bring the markingpins into contact with the upper surface of the lens.

When it is desired to test the accuracy of the grinding of the finishedlenses, a wire I41, Figure 19, may be inserted in apertures I46 providedin the disc 29 of the lens holder, as illustrated by broken lines inFigure 5, so as to extend across the center of the lens holder window 28to designate the horizontal axis of the lens.

My novel lens marking, centering and testing instrument may also bereadily used for marking prisms. When it is desired to use theinstrument in this manner the outer glass 28 of the window 28 may beremoved and another glass inserted having a supplemental prism graduatedscale provided thereon.

Although I have shown and particularly described the preferredembodiments of my invention, I do not wish to be limited to the exactconstruction shown as various changes in the form and relation of theparts thereof may readily be made without departing from the spirit ofthe invention as set forth in the appended claims.

I claim:

1. In a segment selector for bifocal lenses, a support having meansassociated therewith for holding a lens, a pair of caliper elements,carrier means for maintaining said caliper elements in cooperativerelation with a lens supported by said lens holding means so as to havelongitudinal and transverse movements with respect to said lens, saidcarrier means including a frame mounted on the support at one side ofthe lens holding means to reciprocate in either of two directions atsubstantially right angles to each other, means operably connecting thecaliper elements to said frame, means for moving said frame in both saiddirections of movements thereof, including a single lever and mechanismconnecting said lever to th frame and support of such a character thatthe lever moves in unison with the frame when moving said frame in oneof said directions and relative to said frame and support when movingsaid frame in the other of said directions, and scale and pointer meansconnected directly to the frame and support rendered effective by saidmovements of said frame for indicating the degree of said longitudinaland transverse movements of the caliper elements.

2. In a segment locator for bifocal lenses, a support having meansassociated therewith for holding a lens, a pair of caliper elements,carrier means for maintaining said caliper elements in cooperativerelation with the lens supported by said lens holding means so as tohave longitudinal and transverse movements with respect to said lens,said carrier means including a frame mounted on the support at one sideof the lens holding means to reciprocate in either of two directions atsubstantially right angles to each other, adjustable means connectingthe caliper elements to said frame including a pair of relativelymovable supports, means including a single lever connected with theframe to move in unison therewith in one of said directions of movementof the frame and having pivotal connection with said frame and with thesupport for moving said frame in both said longitudinal and transversemovements thereof, scale and pointer means connected directly to theframe and support rendered effective by said movement of said frame forindicating the degree of said longitudinal and transverse movements ofthe caliper elements, and means mounted on the frame independently ofthe support including a fixed scale, a rotatable screw operativelyconnected with said pair of movable supports, and a pointerscrew-threaded on the screw and slidably associated with said scale forproducing relative movement of the,caliper elements toward and from eachother independently of said longitudinal and transverse movementsthereof and for indicating the degree of said relative movement.

3. In a lens testing instrument of the charac ter described, a lensholder, a source of light mounted to be substantially in the opticalaxis of a lens carried by said lens holder, a target interposed betweenthe lens holder and said source of light, a reflector associated withsaid source of light for reflecting light rays on the target and a lenscarried by said lens holder, said reflector being angularly movable toconcentrate light spots from said optical axis to one side thereof, andmeans providing a graduated scale adjacent the lens holder, said scaleextending in the direction of movement of said light rays produced bysaid angular movement of said reflector to be successively illuminatedby said light rays.

4. In a lens testing instrument of the character described, a reflectingtube, a lens holder and a source of light connected with the reflectingtube in spaced relation with respect to each other axially of said tube,a substantially flat reflector angularly movable to concentrate lightspots off the tube axis, and means providing a graduated scale at theend of the tube adjacent the lens holder, said scale being extended inthe direction of movement of the light spots to have successive portionsthereof illuminated during said angular movement of said reflector.

5. An instrument for centering, marking and testing lenses comprising incombination, a supporting member, a lens holder and a source of lightconnected with the supporting member in spaced relation with respect toeach other, a target carried by said supporting member intermediate thelens holder and said source of light, reflector means associated withsaid source of light for reflecting light rays on the target and on alens carried by said lens holder,,said reflector means including asubstantially flat disk connected with said source of light to supportthe same, said disk being mounted to rock about a fixed axis, means forrocking said disk about said axis to vary the concentration of lightspots with respect to the lens, and means providing a lineal graduatedscale adjacent the lens holder for determining the position of at leasta portion of the lens, said scale being extended in a directionsubstantially normal to said axis of pivotal movement of the reflectorto have successive portions thereof illuminated during said pivotalmovement of said reflector.

6. In a lens centering, marking and testing instrument, a reflectingtube, a lens holder and a source of light connected with the reflectingtube in spaced relation with respect to each other axially of said tube,a target mounted in said tube intermediate the lens holder and saidsource of light to be illuminated by rays of light from said lightsource, a pair of caliper elements mounted adjacent the lens holder forlongitudinal and transverse movements with respect to 15 the lens holderto determine the location of the reading segment of a bifocal lenscarried by said lens holder, a reflector associated with said source oflight for reflecting light rays on the target, caliper elements and saidlens carried by said lens holder, said reflector being mounted to swingabout a fixed axis extending substantially normal to the longitudinalmovement of said caliper elements of such a character that light raysmay be successively concentrated on the lens in a direction parallelwith the longitudinal movement of said caliper elements upon pivotalmovement of said reflector.

WILLIAM A. LOCKHART.

